I really do value your opinions and thoughts. I have had that theory for a while and wanted some feedback and thoughts from people who are very smart and really know their stuff.

Gravity to me just seems like a very underrated thing. We see what it can do with galaxies and holding planets while they rotate around the sun so I thought it could help flip a planet on it's side like Uranus or totally reverse a planet's spin like Venus (Earth having the same effect on Venus as it races past us just like the moon slowed the Earth's spin).

Every argument I put up though, you guys had an answer. So thanks for the debate/discussion on this.

I would like to add that recent simulations suggest that it could also have been a head-on collision between two similarly sized objects (4-5 Mars masses each). Less intuitive than the glancing blow between different sized objects, but according to the simulations it's quite possible.

Interesting, I hadn't heard of this. I did some looking and the most relevant article I could find was this one from July, is it the same one you're referring to? The impact angle they used in these simulations is indeed higher (30-35°, which is actually still shallower than statistical average for a collision -- kind of weird to call it 'head-on' in my opinion), though they are not using similar masses for the impactor and target. Maybe there's something more recent that I'm just not finding?

Pretty intriguing result from the above simulation, as it does a better job of reproducing the observed composition of the lunar material. Also causes a great deal more heating for both the debris and the proto-Earth.

BTW I've read somewhere that one model of the interior structure of Uranus says that it has a solid core of ice and rock, and a thick atmosphere starting right from the core's surface, without liquid water/ammonia ocean. If this model is right, then Uranus is a giant titan-like world (or an ice world with atmosphere)! Pressure on its solid surface may reach 1 million atmospheres, and the temperature is about 2000K. In these conditions, water, methane and ammonia don't go into a liquid state, but makes a phase transition from solid state to gaseous. The atmosphere has a huge concentration of these gases, together with hydrogen and helium, but hydrogen does not go into a liquid and metallic state, like on Jupiter and Saturn. The water/ammonia/methane rains may go in higher layers of the atmosphere, but they evaporate before reaching the surface. Neptune, contrary to Uranus, probably has a huge deep ocean of liquid water/ammonia mixture under its atmosphere, so it can be classified as a giant oceania. Temperature of this ocean is quite big too; thousands of Kelvins, but it does not boil due to giant atmosphere pressure.

That's quite interesting; I had no idea the two planets could have such different internal structures. Also, it occurs to me that if that's true, naming Uranus after the god of the sky and Neptune after the god of the sea has been oddly approppriate with their internal structures.

Odd, what's with those pink spots on the first pic? I'm guessing they're not true colour but infrared representations of heat welling up from inside the planet or something?

They look like cloud features. Most likely those should be white. The red channel used here is actually near IR (845 nm) so maybe that's throwing it off slightly. It's not easy to process images like those, so they rarely end up looking just right.